# CVE-2026-64177: linux: In the Linux kernel, the following vulnerability has been resolved: phonet/pep: disable BH around forwarded sk_recei... CVE-2026-64177 is fixed in 33 products on 1 platform, first by DEBIAN-CVE-2026-64177, released July 20, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-64177 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0011 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jul 19, 2026 ## Description In the Linux kernel, the following vulnerability has been resolved: phonet/pep: disable BH around forwarded sk_receive_skb() The networking receive path is usually run from softirq context, but protocols that take the socket lock may have packets stored in the backlog and processed later from process context. In that case release_sock() -> __release_sock() drops the slock with spin_unlock_bh() and then calls sk->sk_backlog_rcv() with bottom halves enabled. Typical sk_backlog_rcv handlers process the socket whose backlog is being drained, so the BH state at entry is irrelevant for the slocks they touch. pep_do_rcv() is different: when the inbound skb targets an existing PEP pipe, it forwards the skb to a different *child* socket via sk_receive_skb(). That helper takes the child slock with bh_lock_sock_nested(), which is just spin_lock_nested() and assumes BH is already off. The same child slock therefore ends up acquired with BH on (process path) and with BH off (softirq path): process context softirq context --------------- --------------- release_sock(listener) __netif_receive_skb() __release_sock() phonet_rcv() spin_unlock_bh() __sk_receive_skb(listener) [BH now ENABLED] [BH already disabled] sk_backlog_rcv: sk_backlog_rcv: pep_do_rcv() pep_do_rcv() sk_receive_skb(child) sk_receive_skb(child) bh_lock_sock_nested(child) bh_lock_sock_nested(child) => SOFTIRQ-ON-W => IN-SOFTIRQ-W Lockdep flags this as inconsistent lock state, and it can become a real self-deadlock if a softirq on the same CPU tries to receive to the same child socket while its slock is held in the BH-enabled path: WARNING: inconsistent lock state inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. (slock-AF_PHONET/1){+.?.}-{3:3}, at: __sk_receive_skb+0x1cf/0x900 __sk_receive_skb net/core/sock.c:563 sk_receive_skb include/net/sock.h:2022 [inline] pep_do_rcv net/phonet/pep.c:675 sk_backlog_rcv include/net/sock.h:1190 __release_sock net/core/sock.c:3216 release_sock net/core/sock.c:3815 pep_sock_accept net/phonet/pep.c:879 Wrap the forwarded sk_receive_skb() in local_bh_disable() / local_bh_enable() so the child slock is always acquired with BH off. local_bh_disable() nests safely on the softirq path. Discovered via in-house syzkaller fuzzing; the same root cause also on the linux-6.1.y syzbot dashboard as extid 44f0626dd6284f02663c. Reproduced under KASAN + LOCKDEP + PROVE_LOCKING, reproducer: https://pastebin.com/A3t8xzCR ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool ol 8 | 0:5.15.0-323.211.3.3.el9uek | [bpftool 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-bpftool-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | bpftool ol 9 | 0:5.15.0-323.211.3.3.el9uek | [bpftool 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-bpftool-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-azure sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.38.1.160000.2.22 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.38.1.160000.2.23 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-uek ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-container ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-container 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-container-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-container ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-container 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-container-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-container-debug ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-container-debug 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-container-debug-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-container-debug ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-container-debug 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-container-debug-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-core ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-core 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-core-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-core ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-core 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-core-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-debug ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-debug 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-debug-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-debug ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-debug 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-debug-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-debug-core ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-debug-core 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-debug-core-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-debug-core ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-debug-core 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-debug-core-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-debug-devel ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-debug-devel 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-debug-devel-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-debug-devel ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-debug-devel 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-debug-devel-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-debug-modules ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-debug-modules 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-debug-modules-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-debug-modules ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-debug-modules 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-debug-modules-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-debug-modules-extra ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-debug-modules-extra 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-debug-modules-extra-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-debug-modules-extra ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-debug-modules-extra 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-debug-modules-extra-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-devel ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-devel 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-devel-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-devel ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-devel 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-devel-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-doc ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-doc 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-doc-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-doc ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-doc 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-doc-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-modules ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-modules 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-modules-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-modules ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-modules 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-modules-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-modules-extra ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-modules-extra 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek-modules-extra-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek-modules-extra ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek-modules-extra 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek-modules-extra-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek64k ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek64k 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek64k-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek64k ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek64k 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek64k-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek64k-core ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek64k-core 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek64k-core-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek64k-core ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek64k-core 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek64k-core-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek64k-devel ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek64k-devel 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek64k-devel-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek64k-devel ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek64k-devel 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek64k-devel-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek64k-modules ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek64k-modules 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek64k-modules-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek64k-modules ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek64k-modules 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek64k-modules-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek64k-modules-extra ol 8 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek64k-modules-extra 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-8-kernel-uek64k-modules-extra-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-uek64k-modules-extra ol 9 | 0:5.15.0-323.211.3.3.el9uek | [kernel-uek64k-modules-extra 0:5.15.0-323.211.3.3.el9uek](https://patchblox.com/security/data/fix/linux/ol-9-kernel-uek64k-modules-extra-0-5.15.0-323.211.3.3.el9uek.md) | Aug 11, 2026 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | linux Debian 12.15 (bookworm) | 6.1.176-1 | [DEBIAN-CVE-2026-64177](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64177.md) | Jul 20, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.94-1 | [DEBIAN-CVE-2026-64177](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64177.md) | Jul 20, 2026 | | Linux | linux Debian 14 | 7.0.12-1 | [DEBIAN-CVE-2026-64177](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64177.md) | Jul 20, 2026 | --- Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.